[Lua][Error]DynationOS:19: attempt to index ? (a nil value)

Alright, first thing I did edit out the rest of the code, so all you guys will have to see, is the actual function with the error, I thought it would be mean of me to put almost 200 lines of code, also I # ed the code for you guys to, and it will be on line 8… not 19.

Spoiler

1.  function login()
2.   term.setTextColor(colors.blue)
3.   print("Account name: ")
4.   term.setTextColor(colors.white)
5.   local user = 
6.   { 
7.     file = fs.open("file.username","r"),  
8.     user = file.readLine(),
9.   }  
10.   local name = read()
11.   if name == (user) then
12.     file.close()
13.     term.setTextColor(colors.blue)
14.  print("Password: ")
15.  local pass = 
16.    { 
17.       file = fs.open("file.password","r"),
18.       pass = file.readLine()  
19.    }
20.      term.setTextColor(colors.white)
21.      local passw = read()
22.      elseif passw == (pass) then
23.      file.close()
24.     User()
25.   else
26.     file.close()
27.     term.setTextColor(colors.red)
28.     print("Sorry account does not exist")
29.     sleep(1.5)
30.     print("Redirecting you to setup")
31.     setup()
32.   end
33. end

{
	file = fs.open("file.username","r"),  
	user = file.readLine(),
}

What on earth?!…

You should use

file = fs.open("file.username","r")
local user = file.readLine()

Where did you even get that table idea?!

You can't access a table from within it's own definition like that. The table isn't defined yet, so there's nothing to access. What you could do instead might be like:

local user = {file = fs.open("file.username","r")} --see, now the table is defined already
user.user = user.file.readLine()

That should work…actually I'm a bit unsure. Why not just make a function that takes a filename as a parameter and returns the username from it? As a bonus it will close the file when it's done.

LBPHacker, on 12 March 2013 - 10:59 AM said:

{
	file = fs.open("file.username","r"),  
	user = file.readLine(),
}

What on earth?!…

You should use

file = fs.open("file.username","r")
user = file.readLine()

Where did you even get that table idea?!

When I needed to have the string in the other file a define variable. So I though that, that would work… but instead I got an error.

ChunLing, on 12 March 2013 - 10:59 AM said:

You can't access a table from within it's own definition like that. The table isn't defined yet, so there's nothing to access. What you could do instead might be like:

local user = {file = fs.open("file.username","r")} --see, now the table is defined already
user.user = user.file.readLine()

That should work…actually I'm a bit unsure. Why not just make a function that takes a filename as a parameter and returns the username from it? As a bonus it will close the file when it's done.

ugh… lol the program I am making already has a ton of functions, but yeah I could see how that could work better.
EDIT: I made it into a function, and it gave me the same error…

function name()
  file = fs.open("file.username","r")
  local user = {file.readLine()}
  file.close()
end

OK, I see you love storing variables in files. Check out this tutorial, it'll help a bit.

LBPHacker, on 12 March 2013 - 11:06 AM said:

OK, I see you love storing variables in files. Check out this tutorial, it'll help a bit.

A bit? That tutorial would make you a pro with storing tables!!

Sorry for the unnessecary post, I just like his tutorial very much :P/>

Meh, I already know everything you went over about tables + some. ^_^/> Nice tutorial though.

You need to return the value, and you also need to use tables appropriately (or not use them). Like so:

function name(filename) -- accepts a string parameter
  local file = fs.open(filename,"r")
  local user = file.readLine() -- don't know why you were putting this in a table
  file.close()
  return user -- returns a string
end

This shouldn't error if you give it a valid filename (feel free to check if the filename exists before calling this if that's a problem). If you're getting that error, then it's because you aren't opening the file for some reason…quite possibly because it doesn't exist.